1. Field of the Invention
The present invention relates to an optical instrument having a ring member which is arranged to be rotatable with respect to a lens barrel, and also slidable in an optical axis direction, and to a control method for an optical instrument.
2. Description of the Related Art
There is known a lens barrel having a ring member, arranged in a zoom lens barrel that is capable of changing focal length, so as to slide in an optical axis direction, and also rotate around the optical axis, for carrying out manual focus adjustment by a rotation operation of this ring member, or carrying out change of focal length by slide operation of the ring member.
With a lens unit that is disclosed in Japanese patent laid-open No. 2011-43706 (laid-open Mar. 3, 2011), a click mechanism is provided for rotating with respect to a lens barrel and moving in an optical axis direction.